The present invention relates to a puller apparatus installed behind a metal extrusion press.
In order to prevent bending or torsion of an extruded metal which is formed by the metal extrusion press, a puller apparatus is typically provided behind a metal extrusion press (hereinafter simply referred to as an extrusion machine) to pull such an extruded metal by a constant tractional force.
A conventional puller apparatus includes one carrier per extrusion machine. When an extruded metal is conveyed onto a runout table, the carrier can clamp the front end of the extruded metal and pull it in a forward direction. A recent extrusion machine provides two carriers for improving extrusion speed, and using a longer runout table to convey a very long extruded metal. To this end, the two carriers are alternately operated to reduce the rest time of the extrusion machine.
Such a puller apparatus typically includes a pair of guide rails mounted on one side of a runout table, and subrails are employed to connect opposite ends of the guide rails. Two carriers are alternately moved around and on the guide rails (Japanese utility model publication No. 55-7284). Another known puller apparatus includes a pair of guide rails above a runout table. Carriers are hung on the guide rails. Only clamps of the carriers are alternately moved to its operative position on the runout table (Japanese utility model publication No. 59-22883).
In the former prior art, since the opposite ends of guide rails are connected through the subrails, the carriers must be moved from one of the guide rails to the other rail via the subrails. The carriers are moved in two different directions on the guide rails and subrails, so that they do not complicate the drive system. Also, the carrier has to be advanced to its foremost position where the subrail is provided independent of the length of a metal to be extruded. This results in loss of time during an operation cycle.
A disadvantage of the latter prior art is that the guide rails interface with the view above the runout table for operating the puller apparatus. And a space must be available on the runout table to enable movement of the carriers, but this arrangement prevents installation of a cooling fan adapted to cool an extruded metal.